Polymerization and cracking of hydrocarbon gas-mineral oil solutions



Oct. 24, 1939. P. A. MAscHwlTz OLYMERIZATION AND CRACKING 0F HYDROCARBON GAS-MINERAL OIL SOLUTIONS Filed June 17, 1935 Patented Oct. 24, 1939 UNITED STATES POLYMERIZATION AND CRACKING OF HY- DROCARBON TIONS GAS-MINERAL OIL SOLU- Percy A. Maschwitz, Chicago, Ill., assigner to The Pure Oil Company, Chicago, Ill., a corporation of Ohio Application June 17, 1935,` Serial No. 27,011

12 Claims.

This invention relates to process and apparatus for simultaneously converting heavy oils or low octane rating naphtha and hydrocarbon gases into high octane rating gasoline. More particularly the invention is concerned with method and apparatus for converting hydrocarbon gases into heavier hydrocarbons under high super-atmospheric pressure without necessitating the use of high pressure compressing equipment.

It is well known that heavy oils and naphthas may be cracked to form lower boiling hydrocarbons by subjecting them to conditions of high temperature and pressure. Under conditions of the samevorder, gases containing oleiines may be polymerized to hydrocarbons normally liquid. At higher temperature, gases consisting mostly of paraflinic hydrocarbons may be cracked to form olefines, which in turn may be polymerized to form liquid hydrocarbons.

It has been the usual practice in the past to carry out each of these processes separately, and in the case of gases, compressors have been employed for charging the gases under high super- 'atmospheric pressures, which entails considerable expense.

In my invention it is only necessary to compress the gases to relatively low super-atmospheric pressures in the gaseous phase, at which pressure they can be pumped in the liquid phase at atmospheric temperatures into the processing apparatus at any desired pressure for a fraction of the cost entailed when the gases are charged in the gaseous phase.

One of the objects of this invention is to provide means for charging gases in the Vliquid phase to a gas conversion process under high' pressure, using compressors operating in the gaseous phase merely to secure sufiicient pressure to bring the gases into the liquid phase prior to charging them to the conversion system. under higher pressures.

Another object of this invention is to provide means to simultaneously polymerize olene gases and crack hydrocarbon oils in one stage under high pressure and further polymerize the olene gases in a separate stage at substantially the same pressure.

A further object of my invention is to provide means for simultaneously degumming under high pressure the combined reaction products from 1 polymerization and cracking zones.

Another object of my invention is to provide means to simultaneously crack gases and hydrocarbon oils, followed by means to separate the gases without material release of pressure, to polymerize the oienes in the separated gases,

and to subsequently treat the reaction products without material release of pressure for the purpose of removing gum, gum-forming bodies and color-imparting bodies.

Another object of this invention is to provide means to simultaneously polymerize olenic gases and to crack hydrocarbon oils under high pref-sure in one stage and to simultaneously polymerize olenic gases and degum the liquid products from the rst stage in a second stage without release of pressure.

A further object of this invention is to provide meansto use liquid hydrocarbons of intermediate boiling range derived from the products of the process as a solvent to dissolve hydrocarbon gases which it is desired to char-ge to the process.

Further objects of my invention will be apparent from. the following detailed description considered in connection with the accompanying drawing of which the single figure is a. diagrammatic elevation of one form of apparatus suitable to the process.

Referring to the drawing, the hydrocarbon oil to be charged to the process iscontained in the tank I and passes through the pipe 2 into the pump 3 through the pipe 4 and control valve 5 into the upper portion of the vessel 6 wherein a stream of gas is caused to flow counter-current to the downwardly flowing oil and partially absorbed therein. The hydrocarbon oil now bearing gases in solution passes out of the vessel 6 at the 'bottom through the pipe 'I into the pump 8. The.'- pump 8 raises the pressure of the charge to the degree necessary for the process and forces the liquid through the pipe 9 into the heating coil Ill which is enclosed in a suitable furnace II. In the coil I the temperature of the reactants is raised sufficiently to cause cracking of the hydrocarbon oil and polymerization of the olenes contained therein which were absorbed from the gas introducd into the vessel 6. If the gases dissolved in the oil in vessel 6 are primarily parafnic, the temperature in coil I0 should be suiliciently high in order to cause cracking of the gases. The reactants leave the coil II) through the pipe I 2 and are cooled by a spray of fluid injected at the point I3. This is preferably an untreated gasoline or light hydrocarbon oil which contains gum or gum-forming and color-producing bodies which it is desirable to remove. The cooling uid is contained in tank It and is pumped by pump I through line I6 and control valve I1 to the point I3. The partially cooled reactants pass through the valve I9 in line I2 into the fractionating tower 2! wherein the hydrocarbons normally liquid are separated from the gases without substantial reduction of pressure. This separation is facilitated by spraying a cooling liquid of the same nature as that used at point i3 into the upper portion .of the tower through the line 23 and the control valve 24.

The gas leaves the tower 2| through the pipe 25 and passes into the heat exchanger 26, then through pipe 21 and control valve 28 into the heating coil 30. Since the heat input required in the coil Sli is considerably less than that which is required in the coil I0, the coil may be preferably placed in the convection or cooler section of the furnace. The gas leaves the heating coil 36 through the pipe 32 and passes into the reaction zone at a temperature sufliciently high to cau-se further polymerization at a pressure not materially reduced. To assist in controlling the temperature of the gases, a portion thereof may be by-passed around heating coil 30 through bypass line 34 and control valve 36. The reaction zone 35 may take any convenient form such as a chamber suitably insulated to prevent heat losses and which may or may not contain catalyst. The reaction zone may be lined on the inside with heat-resisting refractory material such as iire brick cr refractory clay and the like, which may be of a composition or be impregnated with substances calculated to have a catalytic effect to promote the polymerization of the reacting gases. The reaction zone may be lled with catalyst in a granular or porous form, or the catalyst may be supported upon a suitable vehicle. The products of the reaction zone 35 pass into the pipe 31 and through valve 38. Cooling fluid which may be of the same nature as that used at the point I3 and at the top of the fractionating tower 2|, may be introduced through pipe 39 and control valve 40 into the line 31 at point 4|. The mixture passes through the pipe 42 into a reaction zone 44 for the purpose of removing gum., gum-forming and color-imparting bodies. The hot liquid hydrocarbons that are normally liquid leave the fractionating tower 2| through the line 46 and pass through heat exchanger 26 f in which part of their heat is given up to the l will be chan-ged to higher boiling compounds which may be easily separated from liquids boiling within the gasoline range. The reactants leave zone 44 through the pipe 50 and control valve 52 where a considerable reduction in pressure takes place. The reactants continue through pipe 5|) and enter the fractionating tower 55 preferably at a point intermediate the top and bottom thereof. Liquids having a boiling range above that of gasoline are withdrawn from the fractionating tower through pipe 51 and control valve 58. The normally gaseous hydrocarbons and those boiling within the gasoline range leave the tower as vapor through the pipe 59 and pass into the cooler and condenser 6|, then through the pipe 53 into separator 65. Liquids boiling within the gasoline range may be withdrawn through the pipe 61 and control valve 68 while the gases leave the separator at the top through the pipe es. The gases are compressed by the compressor 1| and passed through the pipe 12, cooler and condenser 14, pipe la, into separator 11. The pressure in the separator l1 issuciently high to condense gasoline fractions which are carried as vapor in the gas. These fractions may be withdrawn through pipe 5B andcontrol valve 19. The dry gas leaves the top of the separator 11 through the pipe @l and control valve d2 and passes out of the system.

As an alternative the dry gas may pass through line 8| to line 83 through control valve 35 and be returned to the vessel t for reabsorption in the hydrocarbon oils. At a point intermediate between the top and the bottom ofthe fractionating tower 55, a condensate having a boiling range for the most part higher than that of gasoline, may be withdrawn as a side stream through the pipe 92 and control valve 94 to the cooler 95 and through the pipe 9B into the accumulator tank 91. The oil may be withdrawn from accumulator 91 through the control valve 98 and the line 99 by the pump |00 which forces the oil through pipe |02 and' valve |03 into the top of the vessel 5, thereby returning it to the process as recycle stock. Gas under a suitable pressure may beintroduced from an extraneous source intothe bottom of vessel t through the line |835 and control valve |06 for solution in the hydrocarbon oil. The olenes in the gas will be selectively dissolved and gases with the highest vapor pressure, such as hydrogen, methane and ethane, which are unsuitable to the process, will remain undissolved and leave the system from the top of vessel 6 through pipe |01 and control valve |06.

When the gas charged to the process consists primarily of 4oleimes comprising butylene, propylene and ethylene, the conditions prevalent in the coil ID may vcause suiiicient polymerization to avoid necessity for subsequent polymerization in the reaction zone 35. In such cases the invention provides that the reactants leaving the coil I0 through pipe |2 may enter the by-pass pipe |09 and pass through the control valve ||0 directly into the pipe 42 and the reaction zone 44. In this case the temperatures in zone 44 will be carried higherthan heretofore in order to simultaneously remove the gum, colorand gum-forming bodies from the hydrocarbons boiling Within the gasoline range and cause additional polymerization of the olenic gases.

The gas to be processed by my invention may consist of a mixture of' hydrocarbons such as are produced in the cracking of hydrocarbon oil or gas, or the stabilization of cracked distillate, or from other oil processing operations yielding gases containing ethylene, propylene and/or butylene. Gases produced from the distillation of coal containing olenes may also be employed. Oils suitable for process are any hydrocarbon distillates heavier than gasoline, and low octane naphthas whose initial boiling point is above substantially 200 F.

In carrying out my invention, gases containing from 10% to 100% olenes may be used. The condition however under which the process is operated will vary considerably with the composition of the gas charged. The type of oil which is used as a solvent will also depend to some extent on the character of the gas to be processed. When the gas from an extraneous source is rich in olenes and comprises for the most part butylene, propylene and to a. lesser extent ethylene, with the balance a mixture of paraiiins and hydrogen, gas oils, mineral seal oils, or heavy hyfis , between slightly drocarbondistillates, will be suitable solvents. Gas oil and the like have selective solvent properties in favor of theoleflnic gases. The temperatures at which these gases canbe polymerized are also suitable for the cracking of the gas oil. When the gas to be charged from an extraneous source comprises butane, propane, ethane, methane and hydrgen with only a comparatively small percentage of olefines, a lowoctane naphtha will be the more suitable solvent. The naphtha will tend to dissolve the constituent ofthe gas having the lowest vapor pressure, namely, butane and propane. The low octane haphtha 'and paraiiinicy gases require a higher temperature for processing than the gasoil and oleilne gases. The operation in the coil I will be primarily cracking in this case with less polymer-- ization.

In accordance with my invention the apparatus may be operated over a range of pressure and temperature conditions to meet the requirements of the type oi' charge. The gas may be introduced 'from an extraneous source into the vessel 5 under pressure ranging from 5100 to 300 pounds per square inch. The gases having the highest vapor pressure and which are least desirable to the process are not dissolved'and leave the system at the top of vessel 6 through pipe |01 and control valve |08. The hydrocarbon solvents may be discharged irom the pump 3 into the vessel 5. gl'he solution obtained under atmospheric temperaltures more or less in vessel 5`will bedischarged by the pump 8 under a pressure of from 500 to 1500 pounds per square inch,and may be heated in the r the tower at a temperature of 200 to 350 F.

substantially free of fractions boiling within the gasoline range. I The gases passing through the heat exchanger 26 may be heated to 400 to 600 F. and further heated to 500 to 1000 F. in passing through the coil 30. rAt this range -of temperature and at a pressure not materially reduced from the charging pressure, except for `natural pressure drops` throughthe apparatus, the 'gases enter the zone undergoing treatment therein.v

over a period ranging from 0.25 to I0 minutes. The reactants leaving reaction zone 35 are cooled by another cooling spray before entering the line 42 wherein .they are admixed with the liquid from the bottom of the fractionating tower, 2i.' The 'liquid from fractionating tower 2| has been par tially cooled by passing through the heat ex. changer 26 and the temperature to which the reactants from reaction zone 35 are cooled is sufficient to insure a temperature ofvbetween 450to 650 F. for the mixture in pipe 42 and entering the reaction zone 44. In passing through the con- I trol valve 49 the liquid from theifractionator tower is reduced in pressure sulciently to allow the reactants from zone 35 to enter the line 42. The pressure in zone 44 may range from 400 to 1400 pounds per# square inch and the time oi reaction from 1 to 30 minutes. The mixture of all the products. from reaction zone 44 enters the fractior'iating tower 55 at a pressure reduced to o -super-atmospheric and 100 DOunds per square inch. A suitable temperature gradient is maintained from the top to the bottom of the tower so that only hydrocarbons within the gasoline boiling range and gases are permitted to pass from the top of the tower as vapor. After cooling the separation of the gas and hydrocarbons is eiected in separator 65. -The gas then enters the compressor Il and is increased in pressure to 100 to'300 pounds per square inch. The compressed gas is cooled andenters the separator 11 wherein remaining gasoline fractions are separated and the dry gas may be eliminated from in, coil l0 will preferably be between 800 and 1050" F. In this case the reactants, after the introduction of the cooling spray. may be conducted by a by-pass pipe directly into thezone 44. The zone 4l will in this case be carriedunder a temperature ranging from 500 to 800 F. and will be used for the purpose of simultaneously polymerizing oleilnic gases and forthe treatment or gum, gum-forming and color-forming bodies to facilitate their subsequent removal from the hydrocarbon liquids. The pressure in the zone 44 may be somewhat higher than under the previous condition since the pressure drop encountered in zone 35 will have been eliminated. `This pressure will A be from 500 to 1500 pounds per squareln'ch. Atter the reactants leave the zone M the process`is t operated in the same manner as described previously.

Although the invention is designed to maintain charging pressure throughout the cracking,

^ polymerlzing, and degumming and decolorizing zones, it will be understood that pressures may be dropped somewhat in various parts of the system within the ranges o! pressure disclosed.

What I claim is: 1. A method for simultaneously cracking to heavier hydrocarbons such as gasoline which comprises absorbing said gases in said oil, heating the oil and absorbed gasesto a temperature suiilcient to cause said cracking and converting 'while under a relatively high super-atmosphericpressure, cooling the resulting products to a tem- M drocarbcn oil and converting hydrocarbon gases perature below conversion temperature b'ut above -the normal vaporizing temperature of gasoline,I

separating normally gaseous hydrocarbons from the normally liquid hydrocarbons, further heating l the normally gaseous hydrocarbons to a temperature suiilcient to convert a substantial portion thereof to heavier hydrocarbons, cooling the reaction products to a temperature suiliciently low 4 to prevent further conversion, commingllng said normally liquid hydrocarbons with said reaction products land contacting them with adsorptive catalyst' at a temperature above the vaporizing temperature of gasoline, all without materially reducing the pressure on the system, and separating the normally gaseous products from the normally liquid products subsequent to contact with said-catalyst.

2. Method in accordance with claim l in which the oil and absorbed gas is heated to a temperature of approximately 800 to" "1200o n. under pressures of approximately 500 to 1500 pounds l per square inch. i

3. Method in accordance with claim 1 in which the oil has a boiling range above that of gasoline and the absorbed gases are chiefly olenic, and the oil with its absorbed gas is heated to a temperature of approximately 800 to 1050 F. under pressures of approximately 500 to 1500 pounds per square inch.

t. Method in accordance with claim l in which the oil is of the order of heavy naphtha and the absorbed gases are mainly paramnic, and the oil with its absorbed gas is heated to a temperature above l000 F. under pressures of approximately 500 to 1500 pounds per square inch.

5. Method in accordance with claim l in which the commingled products are fractionated after contact with the adscrptive catalyst in order to "obtain a condensate having a higher boiling range than gasoline, and the condensate is utilined to absorb the gases in the initial step of the process.

6. A method for cracking hydrocarbon oil and for converting gaseous hydrocarbons into higher boiling hydrocarbons which comprises heating said oil and gas in the same stream to a temperature sufficient to cause cracking and conversion under pressure in excess of 500 pounds per square inch, subjecting the oil and gases to said cohditions of temperatureandpressurev for a sufiicientperiod of time to bring about the desired amount of cracking, separating the reaction products into liquids and gases at substantially reaction pressure, subjecting-the resulting gases4 in a separate zone to suitable temperature, Without material reduction-in pressure, for converting further quantities thereof to higher boiling hydrocarbons, commingling the products from the lastinentioned conversion with said liquids, and separating the normally gaseous from the liquid hydrocarbons resulting from the process.

7. Method in accordance with claim 6 in which the commingled products aretreated to produce finished gasoline.. fi..

8. Methodin accordance withclaim `6l in which the gases are absorbed in the oil prior to the heating 'step.v q

9. Method for simultaneously cracking hydrocarbon o il and converting hydrocarbon gases into liquid hydrocarbons which comprises passing a stream of said oil and gases through a heating and reaction zone wherein thev gases are heated' to suitable conversion temperatures. under vhigh zone in order to convert further quantities offsaid divario gas into liquid hydrocarbons and thereafter combining the reaction products from the last mentioned conversion with said normally liquid products, contacting the commingled products with v solid adsorptive catalystf and separating the gaseous from the liquid reaction products after conversion in a second zone whereby to convert 4 substantial lportions thereof into liquid hydrocarbons and thereafter admitting the products from said last mentioned conversion with said normally liquid fractions, and contacting the adrnixed products with an adsorptive polymerizing catalyst, all without substantial reduction ot pressure, fractionating the products subsequent to said catalyst treatment in order to separate the normally liquid from the normally gaseous fractions, eliminating the lighter portions from said last mentioned gaseous fraction, and recycling the heavier portions of said last mentioned gaseous fractions to said rst mentioned conversion zone. f

1l. A method for simultaneously cracking hydrocarbon oil and converting hydrocarbon gases to heavier hydrocarbons suchas gasoline, which comprises absorbing said gases in said oil, heating the oil and Vabsorbed gases to -a temperature i sumcient to cause said cracking and converting while under high super-atmospheric pressure, cooling the resulting products to a temperature below conversion temperature but above the normal vaporizing temperature of gasoline, separating normally' gaseous hydrocarbons from the normally liquid hydrocarbons.contacting the separated gaseous hydrocarbons in a .reaction zone at temperatures ofl 500l000 F. with a polymerizing catalyst in order to effect' additional conversion of gas to gasoline,'all while under gh super-atmospheric pressure, and separating gasoline boiling constituents from. the

reaction products of the process.

l2. Method in accordance with claim 1l in which conversion products from the catalytic step are commingled with said normally liquid hydrocarbons and the commingled products subjected to rening atelevated temperature with catalytic clay prior to separating the gasoline boiling con-v Vstituents'from theproducts-oi the process.

- luriner A. MAscHwrrz. ,I

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